nats-io/nats-server · error

Recovering sources state from index errored: %v

Error message

Recovering sources state from index errored: %v

What it means

A warning logged by recoverSourcesState() during stream recovery when reading the sources index file fails with an error other than not-exist (I/O or permission problem). Recovery proceeds without the persisted sources state, which is rebuilt in memory; mirror/source sequence continuity may be affected.

Source

Thrown at server/filestore.go:12480

		buf = binary.AppendUvarint(buf, ss.Seq)
		buf = binary.AppendUvarint(buf, uint64(len(ss.Ident)))
		buf = append(buf, ss.Ident...)
	}
	fs.mu.RUnlock()

	return fs.writeFileWithOptionalSync(fn, buf, defaultFilePerms)
}

// Lock should be held.
func (fs *fileStore) recoverSourcesState() uint64 {
	// See if we have a sources index file.
	fs.dios.acquire()
	fn := fs.sourcesStatePath()
	buf, err := os.ReadFile(fn)
	fs.dios.release()

	if err != nil && !os.IsNotExist(err) {
		fs.warn("Recovering sources state from index errored: %v", err)
	}

	var sourcesSeq uint64
	if err == nil {
		sourcesSeq, err = fs.decodeSourcesState(buf)
		if err != nil {
			fs.warn("Error decoding sources state: %s", err)
			// Remove the file, and reset collected state (if any).
			_ = os.Remove(fn)
			fs.sources = nil
		}
	}

	if sourcesSeq < fs.state.FirstSeq {
		sourcesSeq = fs.state.FirstSeq
	}
	return sourcesSeq
}

View on GitHub (pinned to 3a66a489d2)

Solutions

1. Inspect the wrapped OS error for permission or disk problems in the store directory
2. Repair I/O issues and restart to recover sources state properly
3. If the index file is corrupt, remove it and let the state rebuild

When it happens

Trigger: Thrown at server/filestore.go:12480 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nats-io/nats-server@3a66a489d2 (2026-09-02). Data as JSON: /api/errors/b33a66322388f520. Report an issue: GitHub.